.bb{
	box-sizing:border-box; /* css3 rec */
    \-moz-box-sizing:border-box; /* ff2 */
    \-ms-box-sizing:border-box; /* ie8 */
    \-webkit-box-sizing:border-box; /* safari3 */
    \-khtml-box-sizing:border-box; /* konqueror */
}
@if user.agent ie6 ie7 {
	.bb{
		behavior:url("boxsizing.htc");
	}
}